AB1644 INCIDENCE, PREVALENCE, AND BURDEN OF SYSTEMIC LUPUS ERYTHEMATOSUS IN URBAN CHINA, 2013-2017: A NATIONWIDE POPULATION-BASED STUDY
Authors: M. LI, C. LI, M. Cao, K. Lu, X. Tang, P. Gao, M. LI, X. Zeng
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Systemic lupus erythematosus (SLE) is becoming a public health concern because of increasing disease and economic burdens. However, epidemiological data on SLE, especially its incidence rate, were limited in China, the world's largest population. <h3>Objectives</h3> To investigate SLE incidence, prevalence, and SLE-associated cost burdens in urban Chinese, stratified by gender, age group, and region, using national administrative data from 2013 to 2017. <h3>Methods</h3> We conducted a population-based study using records from the national databases of Urban Employee Basic Medical Insurance and Urban Resident Basic Medical Insurance in China between 2013 and 2017. Data from over 380 million patients during the study period were analyzed, and a total of 132,258 SLE patients (mean age 43.03 years, standard deviation 15.29; 81.34% female) were identified. Incident cases were individuals with a diagnosis of SLE with a 3-year disease-free period<sup>[1]</sup>. Prevalent cases were defined as patients with at least 1 insurance claim record with the diagnosis of SLE<sup>[2]</sup>. Primary outcomes, including the overall, age-, gender-, and region-specific incidence and prevalence rates of SLE, were estimated by a two-stage approach assuming a Poisson distribution<sup>[3]</sup>. Associated annual costs and hospital visit times were also calculated in both inpatients and outpatients. <h3>Results</h3> The crude incidence and prevalence of SLE in China in 2017 were 14.96 (95%CI, 12.69-17.43) and 50.37 (95%CI, 44.19-56.95) per 100,000 person-years, suggesting an incident population of 0.21 million and a prevalent population of 0.71 million (Figure 1). The average annual rate of increase in prevalence was 16.86% during 2013 and 2017. Crude incidence and prevalence of SLE among females were 28.03 (95%CI, 23.20-33.30) and 99.66 (95%CI, 85.47-114.95) per 100,000 person-years, higher than those among males of 6.42 (95%CI, 4.59-8.55) and 19.31 (95%CI, 14.94-24.24) per 100,000 person-years, with a prevalent rate ratio of 5.16:1. The age-specific incidence and prevalence showed unimodal distributions, both peaked at 30-49 years old in females and at 40-49 years old in males. Estimated annual cost per-capita was US$1,599.34 in SLE patients. Female outpatients had higher costs (US$971.20 vs. US$480.76 in males) with more hospital visits (9.20 times vs. 4.85 times in males), whereas male inpatients had higher costs (US$5,095.53 vs. US$3,774.40 in females). Costs of adolescent and young adult patients were the highest among age groups. All results in sensitivity analyses showed similar trends as demonstrated by the main results aforementioned. <h3>Conclusion</h3> Rapidly expanding SLE population and increasing costs associated with SLE have placed considerable burdens on health systems in China. Continued and enhanced efforts are needed to make long-term care and support more accessible and cost-effective for SLE patients, especially young population. <h3>References</h3> [1]Bae EH, et al. <i>Trend of prevalence and incidence of systemic lupus erythematosus in South Korea, 2005 to 2015: a nationwide population-based study</i>. Korean J Intern Med, 2020. 35(3): p. 652-661. [2]Bernatsky S, et al. <i>A population-based assessment of systemic lupus erythematosus incidence and prevalence--results and implications of using administrative data for epidemiological studies</i>. Rheumatology (Oxford), 2007. 46(12): p. 1814-1818. [3]Zhang C, et al. <i>Incidence of and trends in hip fracture among adults in urban China: A nationwide retrospective cohort study</i>. PLoS Med, 2020. 17(8): e1003180. <h3>Acknowledgements</h3> None. <h3>Disclosure of Interests</h3> None Declared.